JP6977714B2 - Manufacturing method of heat-shrinkable polyester-based label, package, and heat-shrinkable polyester-based label - Google Patents

Description

The present invention relates to a heat-shrinkable polyester-based label formed by rolling a heat-shrinkable polyester-based film into a tube shape and adhering both ends of the film with a solvent. The present invention relates to a heat-shrinkable polyester-based label in which excessive penetration of a solvent in a solvent-bonded portion is unlikely to occur even if the thickness is thin. Further, the present invention relates to a heat-shrinkable polyester-based label having a high peel strength of a solvent-bonded portion even when a polyethylene terephthalate raw material having high crystallinity is frequently used as a film raw material.

In recent years, polyester-based heat with high heat resistance, easy incineration, and excellent solvent resistance has been applied to label packaging, cap seals, integrated packaging, etc. that protect glass bottles or plastic bottles and display products. Heat-shrinkable polyester-based labels obtained from shrinkable films have been widely used, and the amount used is increasing with the increase in PET (polyethylene terephthalate) bottle containers and the like.
However, since heat-shrinkable labels become dust after use, it has recently become necessary to reduce the amount of dust from an environmental point of view, and thin heat-shrinkable labels (thinned heat-shrinkable labels). Is beginning to be used. In addition, there are many demands for heat-shrinkable films having a high shrinkage rate in order to accommodate various containers. Therefore, there is an increasing tendency to form a heat-shrinkable film using a raw material having an increased amount of amorphous material.
Further, as a further environmental measure, there is a heat-shrinkable polyester-based film in which the ratio of PET bottle recycled raw materials is increased.
By the way, in order to form a tubular label from a heat-shrinkable film, it is necessary to overlap and fix one end of the film in the width direction to the other end. As the fixing method, a solvent bonding method (Patent Documents 1 and 2), a method using an adhesive (Patent Document 3), and the like have been conventionally used. Among them, the solvent bonding method is widely used because it can process a tubular label at high speed.

In the process of processing the surfaces of heat-shrinkable polyester films into tubular labels (tubing process) by this solvent bonding method, the speed is increasing in order to improve production efficiency and reduce costs. In order to stably obtain a solvent-bonded portion having high peel strength (adhesive strength) in a high-speed tubing step, it is sufficient to increase the amount of 1,3-dioxolane, which is generally used as an adhesive solvent. When the amount of 1,3-dioxolane applied is increased, in the case of a heat-shrinkable polyester film having a thin thickness and a large amount of amorphous raw material, the solvent permeates from the coated surface side to the back surface side of the film (solvent penetration), and the solvent penetrates to the back surface. Also the solvent adheres. Then, when the tube-shaped label after solvent bonding is wound into a roll, the tube-shaped label is crushed flat, but if solvent penetration occurs in the solvent-bonded portion, the label in contact with the back side of the solvent-bonded portion is formed. In some cases, it adhered and did not function as a tube, or it caused blocking and made it impossible to unravel the roll.
On the other hand, if the amount of 1,3-dioxolane applied is reduced so as not to penetrate the solvent, the amount of 1,3-dioxolane applied tends to vary in the speeded-up tubing process, and it is sufficient if the amount applied is small. There was an inconvenience that a good peel strength could not be obtained. Similarly, when tetrahydrofuran (THF) is used instead of 1,3-dioxolane so as not to penetrate the solvent, the amount of THF applied tends to vary in the accelerated tubing process, and the amount of THF applied becomes small. Has a problem that sufficient peel strength cannot be obtained.

In addition, in order to be environmentally friendly, there is an increasing demand for heat-shrinkable polyester films that use a large amount of PET bottle recycled raw materials. However, since the PET bottle recycled raw material is a polyethylene terephthalate raw material having high crystallinity, it has excellent chemical resistance, and the solvent 1,3-dioxolane shown in Patent Documents 1 and 2 has a high peeling strength at the bonded portion. There was a problem of shortage.

Therefore, a method of adhering with a mixed solvent of 1,3-dioxolane and an organic solvent compatible with 1,3-dioxolane has been invented (Patent Document 4). However, in order to prevent solvent penetration, a step (pretreatment) of applying a poor solvent to the solvent-bonded portion and drying it is required before the solvent-bonding process, which causes a problem of poor work efficiency. Further, as a method of omitting the pretreatment, there is also a method of adhering with a mixed solution of 1,3-dioxolane and a poor solvent of polyester, but if the amount of the poor solvent is small, the effect of suppressing the solvent penetration cannot be obtained, and the amount is too large. Since sufficient peeling strength cannot be obtained in the high-speed tubing process, it is necessary to adjust the mixing ratio of 1,3-dioxolane and the poor solvent according to the type of film.

Japanese Patent No. 3075019 Japanese Patent No. 3452021 Japanese Unexamined Patent Publication No. 2014-43520 International Publication No. 2016/039133

An object of the present invention is to provide a heat-shrinkable polyester-based label and a package having a solvent-adhesive portion that does not cause solvent penetration even when the film is thin and contains a large amount of amorphous raw material. Alternatively, even in the case of a heat-shrinkable polyester-based film using a large amount of PET bottle recycled raw materials, it is an object of the present invention to provide a heat-shrinkable polyester-based label and a package having a solvent-bonded portion capable of stably obtaining high peel strength.

As a result of diligent studies on the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by using a solvent composition composed of a combination of specific types of compounds, and has completed the present invention. rice field.
That is, the present invention has the following configuration.
1. 1. A tubular heat-shrinkable polyester-based label in which both ends of a heat-shrinkable polyester-based film are bonded to each other with a solvent composition, wherein the solvent composition is 1,3-dioxolane and / or tetrahydrofuran (THF) and polyester. A heat-shrinkable polyester-based label, which is a solvent composition containing at least 2N and has a peel strength of 2N / 15 mm or more at the bonded portion.
2. 2. The heat-shrinkable polyester-based label according to 1, wherein the content of polyester contained in the solvent composition is 1% by mass or more and 40% by mass or less.
3. 3. The heat-shrinkable polyester-based label according to any one of 1 and 2, wherein the heat-shrinkable polyester-based film has a thickness of 5 μm or more and 60 μm or less.
4. The heat-shrinkable polyester-based label according to any one of 1 to 3, wherein the heat-shrinkable polyester-based label comprises a laminated film having at least a surface layer of the heat-shrinkable polyester-based film.
5. A package having the heat-shrinkable polyester-based label according to any one of 1 to 4 on at least a part of the outer periphery of the object to be packaged.
6. A method for producing a heat-shrinkable polyester-based label, which comprises overlapping and adhering both ends of the film with a solvent composition containing at least 1,3-dioxolane and / or tetrahydrofuran (THF) and polyester.
7.1, 3-Dioxolane and / or a solvent composition containing at least tetrahydrofuran (THF) and polyester and having a viscosity of less than 100 mPa · s, to which a heat-shrinkable film is adhered by the solvent composition to a heat-shrinkable polyester-based label. A solvent composition for heat-shrinkable polyester-based labels, characterized in that it is used to make.

According to the present invention, even when the thickness of the heat-shrinkable polyester film is thin and there are many amorphous raw materials, solvent penetration does not occur, and even in a high-speed tubing process, or when a large amount of highly crystalline polyethylene terephthalate raw material is used, heat shrinkage occurs. Even in the case of a polyester-based film, it is possible to provide a heat-shrinkable polyester-based label and a package having a solvent-bonded portion that can stably obtain high peel strength.

The heat-shrinkable polyester-based label of the present invention is a tubular heat-shrinkable polyester-based label formed by stacking both ends of a heat-shrinkable polyester-based film and adhering them with a solvent composition. Here, the end portion means an end portion in the width direction (direction along the longitudinal direction), and is a position including a portion within 20 mm from the end portion.
Further, the heat-shrinkable polyester-based film of the present invention is not only a film composed of only one layer of polyester, but also a film having a laminated structure such as polyester / resin other than polyester / polyester, and the outer layers are both polyester-based films. The laminated film is also included.

In the present invention, by containing 1,3-dioxolane and / or both tetrahydrofuran (THF) and polyester in the solvent composition, solvent penetration occurs even when the thickness of the heat-shrinkable polyester film is thin and the amount of amorphous raw material is large. In addition, in the high-speed tubing process, it is possible to provide a polyester-based label having a high peeling strength at the solvent-bonded portion even if it is a heat-shrinkable polyester-based film using a large amount of highly crystalline polyethylene terephthalate raw material.

Since 1,3-dioxolane is a good solvent for polyester and rapidly dissolves the polyester-based film, the obtained solvent-bonded portion has high peel strength. However, polyester films containing more than 25% by mass of polyethylene terephthalate, which is the main component of PET bottle recycling raw materials with high crystallinity, are difficult to dissolve in 1,3-dioxolane, and solvent bonding is performed using only 1,3-dioxolane. However, sufficient peel strength cannot be obtained.
On the other hand, the polyester contained in the solvent composition of the present invention is easily melted by an organic solvent or heat by containing one or more monomer components which can be an amorphous component, and therefore, it can be suitably used as an adhesive. Even if the polyester film contains more than 25% by mass of the polyethylene terephthalate, high peel strength can be obtained by using the solvent composition containing 1,3-dioxolane of the present invention and the polyester. Further, the polyester film can be adhered by melting the polyester with heat and using it as a hot melt agent. However, when the heat shrinkable polyester film is adhered, the polyester film shrinks due to the heat of the hot melt agent. As a result, appearance defects are likely to occur due to wrinkles, and it is difficult to stably apply a constant amount to the polyester film in a high-speed tubing step due to its high viscosity.
That is, by including both 1,3-dioxolane, which is a good solvent for polyester, and polyester, which functions as an adhesive, in the solvent composition, the above-mentioned drawbacks of each can be covered, and even in a high-speed tubing process or PET bottle recycling. Even a heat-shrinkable polyester-based film that uses a large amount of polyethylene terephthalate raw material, which is the main raw material of the raw material, can stably exhibit high peel strength.

On the other hand, THF is inferior to 1,3-dioxolane in the solubility of polyester, but dissolves a polyester-based film, and the solvent-bonded portion has an appropriate peeling strength. In addition, solvent penetration is less likely to occur than with 1,3 dioxolane, so it is suitable for thin-walled films and heat-shrinkable polyester-based films using highly amorphous raw materials. However, if the amount of THF applied is small, the peel strength will be insufficient.
Further, as described above, polyester can be suitably used as an adhesive because it becomes easily soluble in THF by containing one or more monomer components that can be amorphous components or by further heating. As described above, high peel strength can be obtained even if the amount of THF applied is small. Further, as described above, when polyester is melted by heat and used as a hot melt agent, badness occurs.
That is, by including both THF, which is a good solvent for polyester, and polyester, which functions as an adhesive, in the solvent composition, the above-mentioned drawbacks of each are covered, and high peel strength is stably exhibited even in a high-speed tubing step. It will be possible to do. Further, even in a thinned heat-shrinkable polyester film having high amorphous property, solvent penetration is less likely to occur.

In addition to 1,3-dioxolane and / or THF and polyester, the solvent composition of the present invention may be mixed with an organic solvent compatible with 1,3-dioxolane and / or THF. As the organic solvent compatible with 1,3-dioxolane and / or THF, either a good polyester solvent or a poor polyester solvent may be used. Examples of the good solvent for polyester include 1,4-dioxane, tetrahydrofuran, 1,2,2,2-tetrachloroethane, benzene, toluene, xylene and the like. Examples of the poor solvent for polyester include acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, propyl acetate and the like. It is also possible to prevent solvent penetration by mixing a poor polyester solvent with the solvent composition. However, alcohols such as methanol and ethanol, which are also poor solvents for polyester, and water significantly reduce the solubility of polyester contained in the solvent composition, and therefore it is desirable not to mix them with the solvent composition. The organic solvent compatible with 1,3-dioxolane and / or THF can be used alone or in combination of two or more with the solvent composition, with respect to 100 parts by mass of 1,3-dioxolane and / or THF. , 0 to 300 parts by mass, more preferably 0 to 200 parts by mass, and even more preferably 0 to 100 parts by mass.

The polyester used in the solvent composition of the present invention may contain an ethylene terephthalate unit as a main component. Here, "having an ethylene terephthalate unit as a main component" means that the ethylene terephthalate unit is contained in an amount of 50 mol% or more with respect to the total amount of the components of the polyester. However, the ethylene terephthalate unit is preferably 70 mol% or less in 100 mol% of the polyester constituent unit because the chemical resistance becomes stronger and the solubility in organic solvents such as 1,3-dioxolane and THF decreases. More preferably, it is 60 mol% or less. The ethylene terephthalate unit is preferably 5 mol% or more, more preferably 10 mol% or more, out of 100 mol% of the polyester constituent unit.

Examples of the dicarboxylic acid component other than the terephthalic acid constituting the polyester used in the solvent composition of the present invention include aromatic dicarboxylic acids such as isophthalic acid, naphthalenedicarboxylic acid and orthophthalic acid, adipic acid, azelaic acid, sebacic acid and decane. Examples thereof include aliphatic dicarboxylic acids such as dicarboxylic acids and alicyclic dicarboxylic acids.
Examples of the diol component other than ethylene glycol constituting the polyester used in the solvent composition include aliphatic diols such as 1,3-propanediol, 1,4-butanediol, neopentyl glycol, and hexanediol, and 1,4-. Examples thereof include alicyclic diols such as cyclohexanedimethanol and aromatic diols such as bisphenol A.

The polyester used in the solvent composition of the present invention is an aromatic dicarboxylic acid such as isophthalic acid, an aliphatic dicarboxylic acid such as adipic acid, a cyclic diol such as 1,4-cyclohexanedimethanol, or a diol having 3 or more carbon atoms ( For example, a polyester containing at least one of (1,3-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, etc.) and having a glass transition point (Tg) of 70 ° C. or lower is preferable. ..
Further, in the polyester used in the solvent composition, the total of one or more monomer components that can be an amorphous component in 100 mol% of the polyvalent carboxylic acid component or 100 mol% of the polyhydric alcohol component in the total polyester resin is 30. It is mol% or more, preferably 40 mol% or more, and more preferably 50 mol% or more. This is because if the total of the monomer components that can be amorphous components is less than 30 mol%, the solubility in organic solvents such as 1,3-dioxolane is low and the solvent cannot be used.
Examples of the monomer that can be an amorphous component include isophthalic acid, orthophthalic acid, adipic acid, sebacic acid, 1,4-cyclohexanedimethanol, neopentyl glycol, 1,3-propanediol, and 1,4-butanediol. Hexadiol can be mentioned.

The upper limit of the content of polyester contained in the solvent composition of the present invention is preferably 40% by mass or less, more preferably 34% by mass or less, still more preferably 25% by mass or less, and particularly preferably 20% by mass or less. The higher the content of polyester contained in the solvent composition, the higher the viscosity of the solvent composition, and it becomes difficult to stably apply the solvent composition to the polyester film in a constant amount in the high-speed tubing process. This is to become. The lower limit of the polyester content contained in the solvent composition is preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 5% by mass or more, and particularly preferably 8% by mass or more. If the content of polyester contained in the solvent composition is too low, sufficient peel strength cannot be obtained when a polyester film containing polyethylene terephthalate in an amount of more than 25% by mass is adhered, and the solvent composition cannot be sufficiently peeled. When the coating amount is small, the peel strength of the bonded portion is insufficient.
Various additives, thickeners, heat stabilizers, coloring pigments, anticoloring agents, ultraviolet absorbers and the like may be added to the solvent composition of the present invention, if necessary.

The lower limit of the viscosity of the solvent composition is not particularly limited, but if the viscosity is too high, it becomes difficult to stably apply a constant amount in the accelerated tubing step, so that the viscosity is preferably less than 100 mPa · s. , 90 mPa · s or less is more preferable, 80 mPa · s or less is further preferable, and 70 mPa · s or less is particularly preferable.
In the tubing step, it is preferable to apply the solvent composition to the heat-shrinkable polyester film at ^{about 50 to 550 mg / m 2} using a known center seal machine or the like. Further, the coating width of the solvent composition in the tubing step is preferably 1 mm or more in order to suppress peeling of the adhesive portion, and the upper limit is not particularly limited, but the smaller the label area used, the lower the cost, so 10 mm. The following is preferable.

The speed of the tubing step is not particularly limited, but is preferably 300 to 500 m / min in terms of speeding up. After the tubing process, the tubular label is usually folded flat and wound into a roll, and then the label is unwound and cut to a predetermined length to be a final product. You may perform the cutting process without doing so.
The heat-shrinkable polyester label of the present invention has a solvent-bonded portion having a peel strength of 2N / 15 mm or more, preferably 3N / 15 mm or more, and more preferably 4N / 15 mm or more. If the peel strength is 2N / 15 mm or more, troubles such as peeling during use can be prevented. Further, the upper limit of the peel strength of the solvent-bonded portion is less than 15 N / 15 mm. The higher the peel strength is, the more preferable it is, but this is because the peel strength of 15 N / 15 mm or more could not be realized in the present invention. The method for measuring the peel strength follows the method described in Examples.

The thickness of the heat-shrinkable polyester-based film constituting the heat-shrinkable polyester-based label of the present invention is preferably 5 μm or more and 60 μm or less, and more preferably 8 μm or more and 45 μm or less. From the viewpoint of thinning the label, it is more preferably 30 μm or less. The label may be provided with a print layer in a portion other than the adhesive portion.

The heat-shrinkable polyester-based label of the present invention preferably has a heat-shrinkage rate of 40% or more in the main shrinkage direction in warm water at 90 ° C. for 10 seconds. If the heat shrinkage rate is 40% or more, a beautiful shrinkage finish can be obtained. If it is less than 40%, the heat shrinkage force is insufficient, and when the container or the like is coated and shrunk, it does not adhere to the container and an appearance defect occurs, which is not preferable. In the direction orthogonal to the main shrinkage direction, the heat shrinkage rate in warm water at 90 ° C. is preferably 15% or less. If it exceeds 15%, a phenomenon called vertical sinking, in which the vertical direction of the label shrinks, tends to occur, which is not preferable. The heat shrinkage rate in the main shrinkage direction means the heat shrinkage rate in the direction in which the sample shrinks most, and the main shrinkage direction is determined by the length in the vertical direction or the horizontal direction of the square sample. The method for measuring the heat shrinkage rate (%) follows the method described in Examples.

The polyester used in the heat-shrinkable polyester-based label of the present invention preferably contains an ethylene terephthalate unit as a main component. This is because it has excellent strength and heat resistance. The ethylene terephthalate unit is preferably 50 mol% or more, more preferably 60 mol% or more, out of 100 mol% of the polyester constituent unit.
The ethylene terephthalate unit may include a unit derived from a PET bottle recycled material. PET bottle recycling raw materials are PET bottles for beverages processed into flakes and pellets. When forming a polyester-based film, it is preferable to use this PET bottle recycled raw material in an amount of 90% by mass or less based on 100% by mass of the polyester raw material. If a PET bottle recycled raw material in excess of 90% by mass is used, the crystallinity of the polyethylene terephthalate constituting the PET bottle is high, so that the heat shrinkage property of the obtained film may deteriorate. In order to promote recycling, it is desirable to use 20% by mass or more of PET bottle recycled raw materials in 100% by mass of polyester raw materials.
Examples of the dicarboxylic acid component other than terephthalic acid constituting the polyester used in the heat-shrinkable polyester-based film of the present invention include isophthalic acid, aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid and orthophthalic acid, and adipic acid. Examples thereof include aliphatic dicarboxylic acids such as azelaic acid, sebacic acid and decandicarboxylic acid, and alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid.

When an aliphatic dicarboxylic acid (for example, adipic acid, sebacic acid, decandicarboxylic acid, etc.) is contained in the polyester, the content is preferably less than 3 mol% (in 100 mol% of the dicarboxylic acid component). The heat-shrinkable polyester-based label obtained by using a polyester containing 3 mol% or more of these aliphatic dicarboxylic acids tends to have insufficient film waist when worn at high speed.
Further, it is preferable not to contain a polyvalent carboxylic acid having a valence of 3 or more (for example, trimellitic acid, pyromellitic acid and anhydrides thereof). Heat-shrinkable polyester-based labels obtained using polyesters containing these multivalent carboxylic acids are less likely to achieve the required high shrinkage.

Examples of the diol component other than ethylene glycol constituting the polyester used in the heat-shrinkable polyester-based film of the present invention include aliphatic diols such as 1,3-propanediol, 1,4-butanediol, neopentyl glycol, and hexanediol. Examples thereof include alicyclic diols such as 1,4-cyclohexanedimethanol, aromatic diols such as bisphenol A, and the like.
The polyester used in the heat-shrinkable polyester film of the present invention is a cyclic diol such as 1,4-cyclohexanedimethanol or a diol having 3 to 6 carbon atoms (for example, 1,3-propanediol, 1,4-). Polyester containing at least one of (butanediol, neopentyl glycol, hexanediol, etc.) and having a glass transition point (Tg) adjusted to 60 to 80 ° C. is preferable.

Further, the polyester used in the heat-shrinkable polyester-based film of the present invention is one or more kinds that can be an amorphous component in 100 mol% of the polyhydric alcohol component or 100 mol% of the polyvalent carboxylic acid component in the total polyester resin. The total of the monomer components is 15 mol% or more, preferably 16 mol% or more, more preferably 17 mol% or more, and particularly preferably 18 mol% or more. The upper limit of the total of the monomer components that can be the amorphous component is not particularly limited, but 30 mol% is preferable.
Examples of the monomers that can be an amorphous component include neopentyl glycol, 1,4-cyclohexanedimethanol, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,2-diethyl-1. , 3-Propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-isopropyl-1,3-propanediol, 2,2-di-n-butyl-1,3- Examples thereof include propanediol and hexanediol. Among these, neopentyl glycol, 1,4-cyclohexanedimethanol or isophthalic acid is preferably used.

Here, the interpretation of the above-mentioned term "which can be an amorphous component" will be described in detail.

In the present invention, the "amorphous polymer" specifically refers to a case where the measurement with a DSC (differential scanning calorimetry device) does not have an endothermic peak due to melting. Amorphous polymers have not substantially progressed in crystallization and cannot take a crystalline state, or even if they are crystallized, the degree of crystallinity is extremely low.

Further, in the present invention, the "crystalline polymer" refers to a case other than the above-mentioned "amorphous polymer", that is, a case having an endothermic peak due to melting as measured by a DSC differential scanning calorimetry apparatus. A crystalline polymer is one that has or has already crystallized properties that can be crystallized when the polymer is heated.

In general, for a polymer in which a large number of monomer units are bonded, the stereoregularity of the polymer is low, the targetness of the polymer is poor, the side chains of the polymer are large, the polymer has many branches, and the molecules between the polymers are intermolecular. When it has various conditions such as low cohesive force, it becomes an amorphous polymer. However, depending on the state of existence, crystallization may proceed sufficiently to form a crystalline polymer. For example, even if the polymer has a large side chain, if the polymer is composed of a single monomer unit, crystallization may proceed sufficiently and the polymer may become crystalline. Therefore, even if the same monomer unit is used, the polymer may be crystalline or amorphous, and therefore, the expression "can be an amorphous component" is used in the present invention.

Here, in the present invention, the monomer unit is a repeating unit constituting a polymer derived from one polyhydric alcohol molecule and one polyvalent carboxylic acid molecule.

When the monomer unit composed of terephthalic acid and ethylene glycol (ethylene terephthalate unit) is the main monomer unit constituting the polymer, the monomer unit composed of isophthalic acid and ethylene glycol, the monomer unit composed of terephthalic acid and neopentyl glycol, and terephthalic acid Examples include a monomer unit composed of 1.4-cyclohexanedimethanol, a monomer unit composed of isophthalic acid and butanediol, and the like as a monomer-derived unit that can be the above-mentioned amorphous component.

Further, it is preferable not to contain a diol having 8 or more carbon atoms (for example, octanediol or the like) or a trihydric or higher polyhydric alcohol (for example, trimethylolpropane, trimethylolethane, glycerin, diglycerin or the like). Heat-shrinkable polyester-based labels obtained using polyesters containing these diols or polyhydric alcohols are less likely to achieve the required high shrinkage. It is also preferable that diethylene glycol, triethylene glycol and polyethylene glycol are contained as little as possible.
Further, in the polyester, it is preferable to copolymerize the amorphous component in 100 mol% of the polyhydric alcohol component and 100 mol% of the polyvalent carboxylic acid component (that is, in a total of 200 mol%) in the total polyester resin. By copolymerizing, there is no concern about segregation of raw materials, and it is possible to prevent changes in film physical properties due to fluctuations in the composition of film raw materials. Further, the transesterification proceeds by the copolymerization, which is advantageous in increasing the amount of amorphous material and increasing the shrinkage rate in the main shrinkage direction.

In the resin forming the heat-shrinkable polyester film used for the label of the present invention, various additives such as waxes, antioxidants, antistatic agents, crystal nucleating agents, and viscosity reducing agents are included as required. Agents, heat stabilizers, coloring pigments, anticoloring agents, ultraviolet absorbers and the like can be added.
It is also preferable to add fine particles as a lubricant that improves the workability (slipperiness) of the film to the resin forming the heat-shrinkable polyester film in that the tubing process can be speeded up. Any fine particles can be selected. For example, the inorganic fine particles include silica, alumina, titanium dioxide, calcium carbonate, kaolin, barium sulfate and the like, and the organic fine particles include, for example, an acrylic resin. Examples thereof include particles, melamine resin particles, silicone resin particles, crosslinked polystyrene particles and the like. The average particle size of the fine particles is in the range of 0.05 to 3.0 μm (when measured with a Coulter counter), and can be appropriately selected as needed.

As a method of blending the above particles in the resin forming the heat-shrinkable polyester-based film, for example, it can be added at any stage of producing polyester, but at the stage of esterification or after the completion of the transesterification reaction. , It is preferable to add it as a slurry dispersed in ethylene glycol or the like at a stage before the start of the polycondensation reaction to proceed with the polycondensation reaction. Further, a method of blending a slurry of particles dispersed in ethylene glycol or water using a kneaded extruder with a vent and a polyester raw material, or a method of blending dried particles and a polyester raw material using a kneaded extruder. It is also preferable to carry out by a method or the like.

The heat-shrinkable polyester-based film may be subjected to a corona treatment, a coating treatment, a flame treatment, or the like in order to improve the printability and adhesiveness of the film surface.

The heat-shrinkable polyester film of the present invention also includes a laminated polyester film having at least one polyester resin layer. When two or more polyester resin layers are laminated, the polyester resin layer may be a polyester having the same composition or a polyester having a different composition. The layer that can be laminated as another layer is not particularly limited as long as it is a thermoplastic resin layer, but is preferably a polystyrene-based resin layer from the viewpoint of price and heat shrinkage characteristics.
It is preferable to add a thermoplastic resin and / or a rubber component to the polystyrene-based resin. Examples of the thermoplastic resin include styrene resins such as polystyrene, AS resin, and ABS resin having an atactic structure, polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, nylon 6, nylon 66, nylon 12, and nylon 4. , Polypolymer-based resins such as polyhexamethylene adipamide, and polyolefin-based resins such as polyethylene, polypropylene and polybutene.
On the other hand, as the rubber component, a rubber-like copolymer containing a styrene-based compound as a constituent component is preferable, and a random, block or graft copolymer obtained by selecting one or more of each of the styrene and the rubber component and copolymerizing them can be mentioned. Can be done. Examples of such rubber-like copolymers include styrene-butadiene copolymer rubber, styrene-isoprene block copolymer, rubber obtained by hydrogenating a part or all of the butadiene portion thereof, and methyl-butadiene-styrene acrylate. Examples thereof include copolymer rubber, acrylonitrile-butadiene-styrene copolymer rubber, acrylonitrile-alkyl acrylate-butadiene-styrene copolymer rubber, methyl methacrylate-alkyl acrylate-butadiene-styrene copolymer rubber and the like. Since the rubber-like copolymer containing the above-mentioned styrene-based compound as a constituent component has a styrene unit, it has good dispersibility in a polystyrene-based resin having a syndiotactic structure, and has an effect of improving plasticity with respect to the polystyrene-based resin. big. Further, as the compatibility adjusting agent, a rubber-like copolymer containing the above-mentioned styrene-based compound as a constituent component can be preferably used.

On the other hand, other rubber components include natural rubber, polybutadiene, polyisoprene, polyisoprene, neoprene, ethylene-propylene copolymer rubber, urethane rubber, silicone rubber, acrylic rubber, polyether-ester rubber, and polyester-ester. Rubber or the like can be used.

The weight average molecular weight of the polystyrene-based resin is preferably 10,000 or more, and more preferably 50,000 or more. A film having a weight average molecular weight of less than 10,000 is not preferable because the strong elongation characteristics and heat resistance of the film tend to deteriorate. The upper limit of the weight average molecular weight is not particularly limited, but if the weight average molecular weight exceeds 1,500,000, fracture may occur due to an increase in stretching tension, which is not preferable.
As the polystyrene-based resin, various grades are commercially available from various manufacturers, and commercially available polystyrene resins may be used. The other layers may be one layer or two or more layers.

In the heat-shrinkable polyester film of the present invention, the polyester raw material described above is melt-extruded by an extruder to form an unstretched film, and the unstretched film is stretched horizontally or biaxially by a predetermined method shown below. It can be obtained by stretching and heat-treating. When stacking, a plurality of extruders, feed blocks, and multi-manifolds may be used. The polyester can be obtained by polycondensing the above-mentioned suitable dicarboxylic acid component and diol component by a known method. In addition, usually, two or more kinds of chip-shaped polyester are mixed and used as a raw material for a film. When stacking, a plurality of extruders may be used.
When the raw material resin is melt-extruded, it is preferable to dry the polyester raw material using a dryer such as a hopper dryer or a paddle dryer, or a vacuum dryer. After the polyester raw material is dried in this way, it is melted at a temperature of 200 to 300 ° C. and extruded into a film using an extruder. For extrusion, any existing method such as the T-die method and the tubular method can be adopted.

Then, an unstretched film can be obtained by quenching the sheet-shaped molten resin after extrusion. As a method for rapidly cooling the molten resin, a method of casting the molten resin from a base onto a rotary drum and quenching and solidifying the molten resin to obtain a substantially unoriented resin sheet can be preferably adopted.
The obtained unstretched film is, if necessary, heated on a roll at 70 to 100 ° C., preferably 80 to 90 ° C., and then vertically stretched 1.1 to 1.8 times using a speed difference of the roll. The obtained film after longitudinal stretching is preheated at 80 to 120 ° C., preferably 90 to 110 ° C., if necessary, and then 3.0 times or more in the lateral direction (direction orthogonal to the extrusion direction) with a tenter or the like. It is preferably stretched 3.5 times or more and 7 times or less. The stretching temperature is 65 ° C. or higher and 100 ° C. or lower, preferably 70 ° C. or higher and 95 ° C. or lower.
Further, after the transverse stretching, it is preferable to heat-treat at a temperature 1 ° C. to 30 ° C. higher than the stretching temperature. The heat treatment is performed to alleviate the tension state of the film after stretching, and is also effective in adjusting the heat shrinkage rate at the temperature at the time of the heat treatment and reducing the natural shrinkage rate. As a result, the heat-shrinkable polyester-based film of the present invention can be obtained.

The heat-shrinkable polyester-based film of the present invention can be labeled by a conventionally known method. As an example, a heat-shrinkable polyester-based film cut to a desired width is appropriately printed, and the left and right ends of the film are overlapped and joined with the above-mentioned solvent composition to produce a tube film. Cut this tube film to an appropriate length to make a tubular label.
After forming perforations on the above label by a known method, if necessary, cover the PET bottle, place the PET bottle on a belt conveyor, etc., and blow steam into a contraction tunnel (steam tunnel) or hot air. It passes through the inside of a shrink tunnel (hot air tunnel) of the type to be attached. The label is heat-shrinked when passing through these tunnels, so that the label is attached to a bottle container such as a PET bottle.

The package of the present invention is preferably obtained from the heat-shrinkable polyester-based film of the present invention, and preferably a label having perforations or notches covers at least a part of the outer periphery of the object to be packaged and is heat-shrinked. It is what is formed. Examples of the packaging object include PET bottles for beverages, various bottles, cans, plastic containers such as confectionery and lunch boxes, and paper boxes. Normally, when a label obtained from a heat-shrinkable polyester film is heat-shrinked and coated on those packaging objects, the label is heat-shrinked by about 5 to 70% and brought into close contact with the package. .. The label coated on the object to be packaged may or may not be printed.

Hereinafter, the present invention will be described in more detail by way of examples, but the following examples do not limit the present invention, and are included in the present invention when they are modified without departing from the spirit of the present invention. The methods for measuring the physical characteristics of the films obtained in Examples and Comparative Examples are as follows.

[density]
The film was obtained by immersing the film in a density gradient solution (calcium nitrate aqueous solution) according to JIS K7112.

[Hot water heat shrinkage rate]
The film was cut into 10 cm × 10 cm squares along the longitudinal direction and its orthogonal direction (width direction), and immersed in warm water at 90 ° C. ± 0.5 ° C. for 10 seconds under no load for heat shrinkage. Immediately after that, the sample was immediately immersed in water at 25 ° C. ± 0.5 ° C. for 10 seconds, then withdrawn from the water, the vertical and horizontal lengths of the sample were measured, and the values were obtained according to the following formula.
Shrinkage rate = {(length before shrinkage-length after shrinkage) / length before shrinkage} x 100 (%)
In this embodiment, the direction in which the film has the largest shrinkage rate (main shrinkage direction) is the width direction.

[Glass transition point (Tg)]
It was determined according to JIS K7121 using a differential scanning calorimeter (model: DSC220) manufactured by Seiko Electronics Co., Ltd. 10 mg of the unstretched film was heated from 25 ° C. to 120 ° C. at a heating rate of 10 ° C./min to obtain a temperature rise profile. The temperature at the intersection of the extension line of the baseline below the glass transition temperature and the tangent line showing the maximum inclination at the transition portion was defined as the glass transition temperature.

[Solvent bonding method]
While cutting the film to a width of 380 mm, a film roll was manufactured with a winding length of 1000 m in the longitudinal direction. The film is unwound from the film roll, and the adhesive solvent composition is continuously applied in the longitudinal direction so that the coating width is within the range of 4 ± 2 mm on the inside of one end in the film width direction. The coated portion was placed on the other widthwise end of the film, and the film was folded so that the overlapped portion was at the center, and solvent-bonded.
The solvent bonding processing speed was 400 m / min, and the film after solvent bonding was wound around a paper tube at the same speed. The obtained tubular label roll was aged for 24 hours in an atmosphere of 23 ° C. Further, the amount of the solvent applied is arbitrarily adjusted.

[Viscosity of solvent composition]
Measurement was performed using a B-type viscometer (model: BASE L) manufactured by Atago Co., Ltd. under the conditions of a solvent composition temperature of 23 ° C. and a rotation speed of 10 rpm.

[Solvent penetration evaluation]
A tube-shaped label having a winding length of 1000 m after aging obtained by adhesive with a solvent was manually pulled out from the roll surface by 500 m, and when there was a blocking phenomenon, it was judged that the solvent had penetrated and evaluated as follows.
No blocking: Evaluation of solvent penetration ○ (No penetration)
With blocking: Solvent penetration evaluation × (with penetration)

[Measuring method of peel strength of solvent-bonded part]
A sample with a width (corresponding to the length in the longitudinal direction) of 15 mm is circled from the surface layer portion of the tubular label roll having a winding length of 500 m after being pulled out 500 m from the surface layer of the roll during the above-mentioned solvent penetration evaluation so that the solvent adhesive portion is in the center. It was cut out along the circumferential direction (the length should be about 100 mm). The number of samples n was 10. It was set in a universal tensile tester "STM-50" manufactured by Baldwin, and a 180 ° peel test was conducted under the condition of a tensile speed of 200 mm / min. The average value of the 10 samples was taken as the peel strength (N / 15 mm) of the solvent-bonded portion.

<Synthesis example of polyesters A to G and I to J>
In a stainless steel autoclave equipped with a stirrer, thermometer and partial recirculation cooler, 100 mol% of dimethyl terephthalate (DMT) as a dicarboxylic acid component and 100 mol% of ethylene glycol (EG) as a polyhydric alcohol component were added. Ethylene glycol was charged to be 2.2 times the molar ratio of dimethyl terephthalate, and 0.05 mol% of zinc acetate (relative to the acid component) was used as a transesterification catalyst to distill off the produced methanol. While doing so, the transesterification reaction was carried out. Then, 0.225 mol% of antimony trioxide (relative to the acid component) was added as a polycondensation catalyst, and a polycondensation reaction was carried out at 280 ° C. under a reduced pressure of 26.7 Pa to obtain an intrinsic viscosity of 0.70 dl / g. Polyester A was obtained. This polyester A is polyethylene terephthalate. In the production of the polyester A _{, 8000 ppm of SiO 2} (Silicia 266 manufactured by Fuji Silysia Chemical Ltd.) was added to the polyester as a lubricant. Further, in the same manner as described above, the polyesters B, C, D, I and J shown in Table 1 and the polyesters E, F and G shown in Table 2 were synthesized. Further, as a PET bottle recycling raw material, "clear pellets" (manufactured by Yo-PET Bottle Recycling Co., Ltd .; intrinsic viscosity 0.63 dl / g) were used as the chip H.
In the table, TPA is terephthalic acid, IPA is isophthalic acid, OPA is orthophthalic acid, AA is acrylic acid, SA is sebacic acid, CHDM is 1,4-cyclohexanedimethanol, NPG is neopentyl glycol, and BD is 1,4-. Butanediol. The intrinsic viscosity of the polyesters in Tables 1 and 2 is 0.70 dl / g for polyester A, 0.70 dl / g for polyester B, 0.73 dl / g for polyester C, 0.73 dl / g for polyester D, and polyester E. 0.53 dl / g, polyester F 0.98 dl / g, polyester G 0.89 dl / g, polyester H 0.63 dl / g, polyester I 0.70 dl / g, polyester H 0.70 dl / It was g. In addition, each polyester was appropriately formed into chips.

<Manufacturing method of film I>
Each polyester chip obtained in the above synthetic example was separately pre-dried, and as shown in Table 3, the polyester A was mixed at 5% by mass, the polyester B at 5% by mass, and the polyester C at 90% by mass and extruded. I put it in the machine. The mixed resin was melted at 280 ° C., extruded from the T-die, brought into contact with a rotating metal roll cooled to a surface temperature of 30 ° C., and rapidly cooled to obtain an unstretched film having a thickness of 60 μm. The amount of amorphous component in the film is shown in Table 3. At this time, the take-up speed of the unstretched film (rotational speed of the metal roll) was about 20 m / min.
The unstretched film was guided to a tenter, heated to 100 ° C. in a preheating zone, and stretched 5 times in the width direction in a stretching zone having a set temperature of 78 ° C. Subsequently, heat treatment was performed at 82 ° C. for 5 seconds, and then the mixture was cooled. By cutting and removing both edges and winding the film into a roll with a width of 500 mm, a laterally uniaxially stretched film having a thickness of 12 μm was continuously produced over a length of 1100 m. The obtained film was a heat-shrinkable polyester-based film that heat-shrinks only in the width direction. Table 3 shows the heat shrinkage of hot water measured at 90 ° C.

<Manufacturing method of film II>
A horizontal uniaxially stretched film having a thickness of 40 μm was continuously formed over a length of 1100 m in the same manner as Film I, except that polyester D was used instead of polyester C and the thickness of the unstretched film was changed from 60 μm to 200 μm. Manufactured. The obtained film was a heat-shrinkable polyester-based film that heat-shrinks only in the width direction. Table 3 shows the heat shrinkage of hot water measured at 90 ° C.

<Manufacturing method of Film III>
Film I except that the thickness of the unstretched film was changed from 60 μm to 64 μm and the draw ratio was changed from 5 times to 4 times by using 5% by mass of polyester A, 25% by mass of polyester C and 70% by mass of polyester H. A horizontal uniaxially stretched film having a thickness of 16 μm was continuously produced over a length of 1100 m by the same method as in the above. The obtained film was a heat-shrinkable polyester-based film that heat-shrinks only in the width direction. Table 3 shows the heat shrinkage of hot water measured at 90 ° C.

<Manufacturing method of film IV>
Each polyester chip obtained in the above synthetic example was separately pre-dried, and as shown in Table 3, polyester A was mixed at 5% by mass and polyester I at 95% by mass and charged into an extruder. The mixed resin was melted at 280 ° C., extruded from the T-die, brought into contact with a rotating metal roll cooled to a surface temperature of 30 ° C., and rapidly cooled to obtain an unstretched film having a thickness of 100 μm. The amount of amorphous component in the film is shown in Table 3. At this time, the take-up speed of the unstretched film (rotational speed of the metal roll) was about 20 m / min.
The unstretched film was guided to a tenter, heated to 90 ° C. in a preheating zone, and stretched 5 times in the width direction in a stretching zone having a set temperature of 70 ° C. Subsequently, heat treatment was performed at 78 ° C. for 5 seconds, and then the mixture was cooled. By cutting and removing both edges and winding the film into a roll with a width of 500 mm, a laterally uniaxially stretched film having a thickness of 20 μm was continuously produced over a length of 1100 m. The obtained film was a heat-shrinkable polyester-based film that heat-shrinks only in the width direction. Table 3 shows the heat shrinkage of hot water measured at 90 ° C.

<Manufacturing method of film V>
Polyester I was changed to polyester J to obtain an unstretched film having a thickness of 100 μm. The unstretched film was guided to a tenter, heated to 97 ° C. in the preheating zone, and stretched 5 times in the width direction in the stretching zone at a set temperature of 77 ° C. Subsequently, heat treatment was performed at 85 ° C. for 5 seconds, and then the mixture was cooled. By cutting and removing both edges and winding the film into a roll with a width of 500 mm, a laterally uniaxially stretched film having a thickness of 20 μm was continuously produced over a length of 1100 m. The obtained film was a heat-shrinkable polyester-based film that heat-shrinks only in the width direction. Table 3 shows the heat shrinkage of hot water measured at 90 ° C.

<Manufacturing method of film VI>
Using 5% by mass of polyester A, 70% by mass of polyester I and 25% by mass of polyester H, an unstretched film having a thickness of 100 μm was obtained. The unstretched film was guided to a tenter, heated to 93 ° C. in the preheating zone, and stretched 5 times in the width direction in the stretching zone at a set temperature of 73 ° C. Subsequently, heat treatment was performed at 81 ° C. for 5 seconds, and then the mixture was cooled. By cutting and removing both edges and winding the film into a roll with a width of 500 mm, a laterally uniaxially stretched film having a thickness of 20 μm was continuously produced over a length of 1100 m. The obtained film was a heat-shrinkable polyester-based film that heat-shrinks only in the width direction. Table 3 shows the heat shrinkage of hot water measured at 90 ° C.

<Manufacturing method of film VII>
Using the coextrusion method, the core layer forming resin, the skin layer forming resin, and the adhesive layer forming resin are melt-extruded from separate extruders (first to third extruders), and then die (T die). By laminating inside and winding it around a rotating metal roll cooled to 30 ° C by the air knife method and quenching it, the thickness is 100 μm, and it has a three-kind five-layer structure, that is, intermediate layers on both the front and back sides of the core layer. An unstretched film (polystyrene resin laminated sheet) having a structure in which an adhesive layer) was laminated and a skin layer was laminated on the outside of each intermediate layer was obtained. The method for forming each layer of the unstretched film (step up to melt extrusion) is as follows. In the following description, the polystyrene-based mixed resin laminated sheet is referred to as a first layer, a second layer, a third layer, a fourth layer, and a fifth layer in order from the front and back (that is, the surface of the fifth layer is a metal. Roll contact surface). The take-up speed of the unstretched film (rotational speed of the metal roll) at this time was about 20 m / min.
-Formation of the first layer and the fifth layer (skin layer) After pre-drying the above-mentioned polyester A and polyester I using a blender device, 5 parts by mass of the pre-dried polyester A and 95 parts of the polyester I. After mixing with a mass blender, the hopper directly above the first extruder was continuously supplied with a metering screw feeder. Then, the supplied mixture of polyester A and polyester I was melt-extruded from the T die of the single shaft type first extruder at 280 ° C. (laminated on the outside of the intermediate layer laminated on the outside of the front and back of the core layer). It was melt-extruded so as to be). In order to stabilize the extrusion from the T-die, a helical type and parallel type gear pump was interposed between the extruder and the T-die.
-Formation of the second layer and the fourth layer (adhesive layer) After the tip K is pre-dried using a blender device, the pre-dried tip K is placed in a hopper directly above the second extruder with a metering screw. It was continuously supplied by the feeder. Then, the supplied chip H was melt-extruded from the T-die of the uniaxial type second extruder (melt-extruded so as to be laminated on the outside of the front and back surfaces of the core layer). The temperature of the second extruder was adjusted to 200 ° C. Further, as in the case of extrusion by the first extruder, a helical type and parallel type gear pump was interposed between the extruder and the T die in order to stabilize the extrusion from the T die.
-Formation of the third layer (core layer) After the chips L, M, and N are pre-dried using a blender device, the chips L, M, and N are continuously placed in a mixing mixer with a metering screw feeder. Supply separately. The supply amount of the chip L was 43% by mass, the supply amount of the chip M was 43% by mass, and the supply amount of the chip N was 14% by mass. Then, the mixed raw materials of the chips L, M, and N mixed in the mixing mixer were continuously and separately supplied to the hopper directly above the third extruder by a metering screw feeder. Then, the supplied chips L, M, N (mixed ones) were melt-extruded from the T die of the single shaft type third extruder. The temperature of the third extruder was also adjusted to 200 ° C. Further, as in the case of extrusion by the first extruder and extrusion by the second extruder, a helical type and parallel type gear pump is interposed between the extruder and the T die in order to stabilize the extrusion from the T die. ..
In the extrusion of the resin by each of the above extruders, the discharge amount of the first to third extruders in the formation of the unstretched film is the first layer / second layer / third layer / fourth layer / fifth layer. The thickness ratio was adjusted to be 24/2/48/2/24.
The obtained unstretched film was heated to 100 ° C. in the preheating zone and stretched 5 times in the width direction in the stretching zone having a set temperature of 80 ° C. Subsequently, heat treatment was performed at 88 ° C. for 5 seconds, and then the mixture was cooled. By cutting and removing both edges and winding the film into a roll with a width of 500 mm, a laterally uniaxially stretched film having a thickness of 20 μm was continuously produced over a length of 1100 m. The obtained film was a heat-shrinkable polyester-based film that heat-shrinks only in the width direction. Table 3 shows the heat shrinkage of hot water measured at 90 ° C.

[Example 1]
A solvent composition prepared by mixing 1,3-dioxolane / acetone / polyester E at 22/68/10 (mass ratio) ^{was applied to film I in a width of 4 mm so as to be 300 mg / m 2,} and the processing speed was 400 m /. Solvent adhesion was performed in minutes to obtain a tubular label roll. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 4. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.

[Example 2]
The evaluation was carried out in the same manner as in Example 1 except that the solvent composition in which 1,3-dioxolane / acetone / polyester E was mixed at 45/45/10 (mass ratio) ^{was applied so as to be 100 mg / m 2.} The solvent bonding conditions and are shown in Table 4. In each case, there was no penetration of the solvent, the peel strength of the solvent-bonded portion was high, and the label was good.

[Examples 3 to 8]
The compounding ratios of the film and the solvent composition were variously changed and evaluated in the same manner as in Example 1. Table 4 shows the solvent bonding conditions and the conditions for each example. In each case, there was no penetration of the solvent, the peel strength of the solvent-bonded portion was high, and the label was good.

[Comparative Example 1]
A tubular label roll was obtained in the same manner as in Example 1 except that a solvent containing only 1,3-dioxolane was used. The solvent bonding conditions and results are shown in Table 4. There was penetration of the solvent, which was not preferable as a label.

[Comparative Example 2]
A tubular label roll was obtained in the same manner as in Example 1 except that a solvent composition in which 1,3-dioxolane / acetone was mixed at a ratio of 50/50 (mass ratio) was used. The solvent bonding conditions and results are shown in Table 4. Although there was no penetration of the solvent, the peel strength of the solvent-bonded portion was small, which was not preferable as a label.

[Comparative Example 3]
A tubular label roll was obtained in the same manner as in Example 1 except that a solvent containing only 1,3-dioxolane was used for Film III. The solvent bonding conditions and results are shown in Table 4. Although there was no penetration of the solvent, the peel strength of the solvent-bonded portion was small, which was not preferable as a label.

[Comparative Example 4]
An attempt was made to obtain a tubular label roll in the same manner as in Example 1 except that a solvent composition in which 1,3-dioxolane / polyester F was mixed at 70/30 (weight ratio) was used. The solvent bonding conditions and results are shown in Table 4. Since the viscosity of the solvent composition was too high, the solvent composition could not be applied ^{to the film in a width of 4 mm so as to be 50 mg / m 2 or more.}

[Example 9]
A solvent composition prepared by mixing THF / polyester E at a ratio of 90/10 (mass ratio) ^{was applied to the film IV at a width of 4 mm at 250 mg / m 2,} and solvent-bonded at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 4. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.

[Example 10]
A solvent composition prepared by mixing THF / polyester F at 80/20 (mass ratio) ^{was applied to film IV in a width of 4 mm so as to be 250 mg / m 2,} and solvent-bonded at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 5. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.

[Example 11]
A solvent composition prepared by mixing THF / polyester G at a ratio of 95/5 (mass ratio) ^{was applied to the film IV at a width of 4 mm at 250 mg / m 2,} and solvent-bonded at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 5. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.

[Example 12]
A solvent composition prepared by mixing THF / polyester E at a ratio of 60/40 (mass ratio) ^{was applied to film IV in a width of 4 mm at a rate of 100 mg / m 2,} and solvent-bonded at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 5. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.

[Example 13]
A solvent composition prepared by mixing THF / polyester E at a ratio of 90/10 (mass ratio) ^{was applied to the film V at a width of 4 mm at 250 mg / m 2,} and solvent-bonded at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 5. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.
[Example 14]
A solvent composition prepared by mixing THF / polyester F at a ratio of 80/20 (mass ratio) ^{was applied to the film VI with a width of 4 mm so as to be 250 mg / m 2,} and solvent-bonded at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 5. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.

[Example 15]
A solvent composition prepared by mixing THF / polyester E at a ratio of 60/40 (mass ratio) ^{was applied to the film VI with a width of 4 mm so as to be 100 mg / m 2,} and solvent-bonded at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 5. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.
[Example 16]
A solvent composition prepared by mixing THF / polyester E at a ratio of 90/10 (mass ratio) ^{was applied to film VII at a width of 4 mm at a rate of 250 mg / m 2,} and solvent bonding was performed at a processing speed of 400 m / min to form a tube. A label roll was obtained. In addition, the presence or absence of solvent penetration and the peel strength of the solvent-bonded portion were measured by the above-mentioned method, and the solvent-bonding conditions and results are shown in Table 5. There was no penetration of the solvent, the peel strength of the solvent-bonded part was high, and the label was good.

[Comparative Example 5]
A tubular label roll was obtained in the same manner as in Example 12 except that a solvent containing only THF was used. The solvent bonding conditions and results are shown in Table 5. The peel strength of the solvent-bonded portion was low, which was not preferable as a label.

[Comparative Example 6]
A tubular label roll was obtained in the same manner as in Example 15 except that a solvent containing only THF was used. The solvent bonding conditions and results are shown in Table 5. The peel strength of the solvent-bonded portion was low, which was not preferable as a label.

[Comparative Example 7]
An attempt was made to obtain a tubular label roll in the same manner as in Example 9 except that a solvent composition in which THF / polyester G was mixed at 40/60 (mass ratio) was used. The solvent bonding conditions and results are shown in Table 5. Since the viscosity of the solvent composition was too high, the solvent composition could not be applied ^{to the film in a width of 4 mm so as to be 1 g / m 2 or less.}

The heat-shrinkable polyester-based label of the present invention can meet the demand for thinning for the purpose of reducing the amount of dust, is less likely to cause problems such as solvent penetration, and has high peeling strength at the bonded portion. It is useful as. Further, even if a heat-shrinkable polyester-based film using a large amount of highly crystalline PET bottle recycled raw material is used, the peeling strength of the solvent-bonded portion is high, which is also useful as a label for beverage bottles.

Claims (1)

A solvent composition containing at least 1,3-dioxolane and / or tetrahydrofuran (THF) and a polyester having a viscosity of less than 100 mPa · s, and a heat-shrinkable film is adhered to the solvent composition to prepare a heat-shrinkable polyester-based label. A solvent composition for heat-shrinkable polyester-based labels, which is characterized in that it is used for a heat-shrinkable polyester-based label.